1. Field of the Invention
The present invention relates to man-made devices to replace the natural heart. The invention relates more specifically to a magnetohydrodynamic artificial heart which pumps human blood without using moving parts.
2. Background Art
Each year an estimated 400,000 Americans suffer from end-stage heart disease. However, only about 3,000 human hearts become available each year for transplantation. There are several industry sources that produce artificial hearts which could be used for transplantation, but all of these artificial heart designs depend on mechanical approaches for operation in conjunction with internal and external prime-power sources that provide only a limited time of operation before recharging or replacement is required. Examples of prior patents that relate to artificial heart replacement devices or to natural assist devices, include the following:
3,568,214Goldschmied3,768,931Willis Jr.3,874,002Kurpanek4,152,785Shumakov et al4,599,083Perlov et al4,621,617Sharma4,650,485Della Sala4,869,656Della Sala6,074,365Hahndel et al6,123,724Denker6,251,061Hastings et al
U.S. Pat. No. 4,152,785 to Shumakov et al disclose an artificial heart for clinical and experimental conditions and having dimensions which correspond to a natural heart. This device is apparently designed to work with external working media and pumps.
U.S. Pat. No. 4,599,083 to Perlov et al disclose an artificial implantable heart which employs a plurality of permanent magnets and an electromagnetic field to move a diaphragm to pump blood. A similar device designed as a natural heart assist device is disclosed in U.S. Pat. No. 6,123,724 to Denker.
U.S. Pat. No. 6,074,365 to Hahndel et al disclose a blood pump which employs a magnetofluid-supported electromagnetic drive and an elastic membrane.
U.S. Pat. Nos. 4,650,485 and 4,869,656 to Della Sala discloses another form of ferromagnetic-fluid pump using an oscillating membrane.
U.S. Pat. No. 3,874,002 to Kurpanek discloses use of cobalt rare-earth magnets to move elastic diaphragms in response to bistable electro-magnetic pumping action. U.S. Pat. No. 3,768,931 to Willis Jr. discloses a similar concept.
U.S. Pat. No. 6,251,061 to Hastings et al disclose an assist device comprising a compressor using a ferrofluid to compress opposite sides of the natural heart. Another type of electromagnetic compressor is shown in U.S. Pat. No. 4,621,617 to Sharma.
U.S. Pat. No. 3,568,214 to Goldschmied discloses an artificial heart pump which employs an electrically conductive fluid and a pulsating magnetic field to move the fluid back and forth as a pumping device using deformable sheets or diaphragms to propel blood.
One of the principal disadvantages of these prior art designs is that they employ moving parts. Moving parts imply friction, wear and fatigue which further imply limited periods of reliable use. Repair or replacement of an artificial heart or heart assist device, requires further major surgery beyond the original installation procedure. Such surgery means use of a heart lung bypass machine and an extensive period of time for the patient to be under general anesthetic. Of course, it also implies entry into the chest cavity and an extensive period of pain and discomfort to recover from the surgery, as well as the need for pain medication and the use of drugs to ward off infection and stroke. Moreover, moving parts can cause dangerous blood clotting that can travel through the circulatory system and cause other problems such as stroke.
Therefore, there is an ongoing need for an artificial heart apparatus or heart assist apparatus which is inherently more durable and more reliable than existing designs. It would be highly advantageous if it were possible to provide such a device implemented in a manner which obviated all moving parts.